Mitsubishi Electric MELSEC iQ-F Series - Behavior When an Active Step Is Activated

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8 SFC PROGRAM
8.6 SFC Program Execution
Behavior when an active step is activated
When an active step is activated, the step behaves as follows.
Series sequence
Selective sequence
■Divergence
The transition condition is checked starting from the left side, and, if the destination of the branch where the transition
becomes TRUE is an active step, the same operation as the series sequence is performed. In the same manner as in the
normal selective sequence, the transition condition is not checked in the lines other than the branch where the double start
becomes TRUE.
■Convergence
The same operation as the series sequence is performed.
Simultaneous sequence
■Divergence
All steps below the transition become active in the next scan.
■Convergence
The transition source becomes inactive. The coil HOLD step [SC] holds operation.
When the transition (2) becomes TRUE, the step (1) becomes
inactive.
The step (3) of the transition which is supposed to be multi-
activated is activated.
When the transition (2) becomes TRUE, the step (1) becomes
inactive.
The step (3) of the transition which is supposed to be multi-
activated is activated.
When the transition (1) becomes
TRUE, the steps (2) to (5) which are
supposed to be multi-activated at
the next scan are all activated.
(1)
(3)
(2)
(1)
(2)
(3)
(3)
(1)
(2) (4) (5)